Lee, whose last day was Friday, says that he wants to spend more time with his family

There have been some pretty exciting developments out of mobile payments company Square recently. Just this week, for example, it premiered Square Order an app that will allow users to order food in advance from cafes and restaurants and then pick them up without having to wait in line. Last month it debuted a new pickup feature, along with inventory tracking for sellers.

Now, the man who was behind those new features, the company's long time Chief Technology Officer Bob Lee, is stepping down from his post.

While no official announcement has been made, Square employees have put up pictures of his going away party on Twitter, and the company also confirmed the departure to VatorNews.

“Bob was our 13th employee, and over the past four years he helped establish and expand our infrastructure as we grew from a handful of beta merchants into a company that supports millions of customers,” a Square spokesperson said in a statement. “We’re grateful to Bob for all he’s done and we wish him the best in his next adventure.”

The spokesperson also confirmed that Lee's last day the company was Friday.

Here is one of those pictures from the party, featuring Square CEO Jack Dorsey:

Lee has worked at Square since January 2010, and has been CTO at the company since 2011. Prior to that, he worked at Google as a staff software engineer for nearly five and half years, and spent a little over a year as a technical architect at AT&T.

In a blog post put up on Friday, Lee stated his reasons for leaving: to spend more time with his family.

"Today I’m proud (and a little sad) to share that after 4½ years, I’m stepping down from my full time role at Square so I can take a break with my family. In the meantime, I’ll continue my involvement with Square as an owner and advisor," he wrote.

To wife and kids, he thanked them for their "support, patience and understanding while I helped create Android and then Square."

"I promise to slow down and stay home for awhile, at least until you grow tired and tell me to go back to work," he wrote.

Maybe it's my cynical nature, but I have to wonder if there is another reason that Lee decided that now is a good time to leave, and, specifically, if it has anything to do with the company's scuttled IPO plans.

Square was said to entertaining the thought of an IPO this year. The rumors were making their rounds—supposedly of talks with banks, like Goldman Sachs and Morgan Stanley. And Square hired former Salesforce.com exec Sarah Friar as its new CFO last year.

Dorsey, however, scuttled those plans in February due to problems with revenue. Namely, the company is not profitable.

Square is on track to generate $1 billion in sales this year from the $30-or-so billion in transactions it expects to process, according to a report from the Wall Street Journal. However, some 70-80% of that revenue gets funneled back to credit card companies.

The company has raised $341 million in capital, at a $5 billion valuation, but was worried that it would have trouble maintaining that kind of market cap on a public market.

It would not shocking to find that Lee had held out a while longer, hoping to be profit from the company's IPO, but decided to leave once it was clear that was no longer going to happen in the immediate future. Of course that is pure speculation on my part.